1. Field of the Invention
The present invention relates to ceramic sinter suitable for sliding member and wear resistant member using thereof. The present invention relates further to ceramic sinter suitable for electronic components such as substrates or the like and electronic component member using thereof.
2. Description of the Related Art
So far, for wear-resistant member such as cam rollers, bearing balls, check balls, wearing plates and plungers used for industrial machinery and automobiles, metal products have been used much. However, when metal products are used in the places mentioned above, due to friction these components tend to be heavily worn to result in an inability of exhibiting prescribed performance or, when more heavily worn, to result in being damaged. These metal products, being heavy, are unsuitable for lightweight or high performance use. Further, the metal products, being low in heat-resistance and corrosion-resistance, are short of durability under severe circumstances, resulting in being less economic. Accordingly, high performance substitutes for the metal products are in demand.
To solve these problems, in recent years, the ceramic sinter is in use as wear-resistant components. The ceramic sinter, being superior to the metal components in wear-resistance, can maintain the prescribed performance and are not damaged for a long time to result in cost saving. In addition, being lightweight compared with the metal components higher speed rotation can be made possible.
However, when the ceramic sinter described above is used in machinery, though the ceramic sinter itself does not wear, the components in contact with the ceramic sinter tend to be worn on the contrary. Those aforementioned things have caused problems in wear-resistant components used in fuel injectors of such as automobiles, in particular in cam rollers. The reason for this is that hardness of the ceramic sinter is higher than that of the metal components in contact therewith.
To solve these problems, it is considered for all the components to be constituted of the ceramic sinter. However, because of difficulties in machining and less economics, that is not yet in realization. In addition, since the wear of opponent members (members in contact with ceramic sinters) is largely influenced by the surface state of the ceramic sinter, several attempts to improve the surface state thereof were tried. As examples of the above, specifying a distance between adjacent convex portions on the surface as a degree of waviness was tried, which expresses the macroscopic roughness of the surface of the ceramic sinter, for example, to 500 xcexcm or less, to form micro-cracks on the surface, or to specify a surface roughness to be 0.005 xcexcm to 0.02 xcexcm and surface porosity to be 0.5% or more and 8% or less. Though the wear of the opponent member is alleviated due to the above provision of the surface state, the wear of the opponent member is still occurring.
By contrast, in the field of electronic industry, in substrates for mounting high power semiconductor components or the like, a metal plate such as copper plate is bonded onto a ceramic substrate to form a ceramic printed wiring board. The ceramic sinter, being excellent in insulation, heat-resistance and thermal conduction, is preferably used for the substrates and heat sinks.
However, when the ceramic sinter is used as the substrate, bonding strength with metal being poor, peeling and damage tend to occur. Accordingly, the composition and structure of the ceramic sinter are controlled to enhance the bonding strength with the metal, thereby preventing the peeling and damage from occurring. However, these problems are still occurring.
Accordingly, an object of the present invention is to provide, for general industrial machinery, ceramic sinter and wear resistant member capable of suppressing wear of an opponent as large as possible. Another object of the present invention is to provide, for electronic components or the like, ceramic sinter excellent in bonding with metal and electronic component member using thereof.
A first aspect of the present invention is that skewness of ceramic sinter at a contact surface is xe2x88x922 or more and 0 or less, and depths of micro-cracks formed on the contact surface are 5 xcexcm or less.
In addition, in the ceramic sinter, in the range of the depth of up to 500 xcexcm from the contact surface, an area that pores occupy per unit area (1 mm2) does not exceed 5%.
The ceramic sinter like this preferably consists of at least one kind selected from a group consisting of for instance silicon nitride, zirconia, silicon carbide, cermet, SIALON, aluminum nitride and alumina.
A second aspect of the present invention relates to wear-resistant member. The present wear resistant member is preferable for the ceramic sinter to have hardness Hv of 100 or more and strength of 300 MPa or more.
The wear-resistant member of the present invention consists of ceramic sinter, the skewness of a sliding contact surface of the ceramic sinter with other member being xe2x88x922 or more and 0 or less, the depths of the micro-cracks at the sliding surface being 5 xcexcm or less.
The present wear resistant member preferably consists of at least one kind selected from a group consisting of for instance silicon nitride, zirconia, silicon carbide, cermet and SIALON. The present wear resistant member can be preferably used for cam rollers, bearing balls, check balls, wearing plates, plungers or rollers.
The aforementioned wear resistant member is preferable to have hardness Hv of 1300 or more and strength of 600 MPa or more. In addition to this, in the range of a depth up to 500 xcexcm from the sliding contact surface, an area of pores is preferable not to exceed 5%.
A third aspect of the present invention relates to an electronic component member. The present electronic component member consists of ceramic sinter, the skewness at a bonding surface of the ceramic sinter with other member is xe2x88x922 or more and 0 or less, the depths of micro-cracks at the bonding surface not exceeding 5 xcexcm.
The present electronic component member is preferable to be used for substrates, heat sinks or the like for instance. The electronic component member like this is preferable to be consisting of at least one kind selected from a group of for instance aluminum nitride, silicon nitride and alumina. The present electronic component member is preferable to have thermal conductivity of 130 W/mxc2x7K or more.
In the present electronic component member, for instance a metal plate can be directly bonded or by use of other method to a bonding surface to use. In the present electronic component member, the skewness at the bonding surface is more preferable to be xe2x88x921 or more and 0 or less, the depths of the micro-cracks not exceeding 5 xcexcm.
In the present ceramic sinter, the skewness at the contact surface is set at xe2x88x922 or more and 0 or less, the depths of the micro-cracks formed on the contact surface at 5 xcexcm or less. Thereby, the ceramic sinter can be prevented from wearing itself and an opponent member. Such effects can be obtained particularly when the opponent member consists of metal that is subject to wear compared with the ceramic sinter. The present ceramic sinter, when the skewness at the contact surface is xe2x88x922 or more and 0 or less and the depths of the micro-cracks formed on the contact surface are 5 xcexcm or less, can enhance bonding with elements and metal plates.
In the present ceramic sinter, in the range of the depth of up to 500 xcexcm from the contact surface, an area that pores occupy is made not to exceed 5%. Thereby, the ceramic sinter itself can be improved in its strength and the opponent member can be suppressed from wearing. In the range of up to 500 xcexcm from the contact surface, the area that pores occupy can be made not to exceed 5%, thereby the bonding at the contact surface being improved.
As materials that constitute such ceramic sinter, at least one kind selected from a group of silicon nitride, zirconia, silicon nitride, cermet, SIALON, aluminum nitride and alumina can be used. Thereby, the ceramic sinter of excellent strength and thermal conduction can be fabricated with ease.
In the present wear resistant member, the skewness of the sliding contact surface that tends to wear other members due to sliding against the other member in particular is set at xe2x88x922 or more and 0 or less. Thereby, wear of the other member consisting of metal or the like can be remarkably reduced. As materials of such wear resistant member, at least one kind selected from a group of silicon nitride, zirconia, silicon carbide, cermet and SIALON can be used. Thereby, the strength and toughness of the wear resistant member can be secured, wear of the wear resistant member itself can be suppressed, and the wear resistant member can be fabricated with ease.
The aforementioned wear resistant member can be used for the member such as for instance cam rollers, bearing balls, check balls, wearing plates, plungers and rollers that rub against each other with high-speed to tend to wear the opponent. Thereby, machinery using thereof can be prevented from damaging and performance deterioration can be suppressed from occurring. In order to use for the above purpose, the present wear resistant member is preferable to have hardness Hv of 1300 or more and strength of 600 MPa or more. In the present wear resistant member, the skewness at the sliding contact surface is set at xe2x88x921 or more and 0 or less, the depths of the micro-cracks not exceeding 1 xcexcm. Thereby, wear of the other member can be further suppressed.
In the present electronic component member, the skewness of the surface that bonds components or circuitry in particular is set at xe2x88x922 or more and 0 or less and the depths of the micro-cracks at not exceeding 5 xcexcm. Thereby, bonding strength between the components and circuitry can be heightened. The electronic component member like this can be used for the member that is subject to expose to vehement temperature variation, such as substrates and heat sinks in particular. Thereby, peeling and damage due to thermal stress can be suppressed.
For an electronic component member like this, at least one kind selected from a group of for instance aluminum nitride, silicon nitride and alumina can be used. Thereby, characteristics such as strength and thermal conduction can be controlled. The present electronic component member, when used for the substrates, heat sinks or the like, is preferable to have thermal conductivity of 60 W/mxc2x7K or more, more preferable being 130 W/mxc2x7K or more. The present electronic component member can be directly bonded to the metal plates or the like, resulting in enhancement more than ever of bonding strength. In the present electronic component member, the skewness at the bonding surface is made xe2x88x921 or more and 0 or less, and the depths of the micro-cracks are made not to exceed 1 xcexcm. Thereby, bonding strength can be further enhanced.